PULAU AYER, Indonesia -- Indonesia has so many islands it has not been able to count them all and is having a hard time finding names for them.

From coral-fringed atolls to jungle-clad volcanoes thrusting up from the ocean, its chains of islands sprinkled along the equator make up the world's biggest archipelago.

Officially there are about 17,000 islands, but that number may drop as one minister fears hundreds of islands might vanish because of rising sea levels from global warming.

So, before it's too late, the country aims to complete its first detailed survey this year, spurred on by worries ranging from sovereignty disputes to climate change.

Even near the capital, there is confusion over the numbers.

Pulau Ayer, or Water Island, is one of a string of islands just north of Jakarta. This tiny dot of an island is part of a chain called Pulau Seribu, or Thousand Islands. Depending on who you ask, there are between 100 and 145 islands.

"How can you manage the islands if you don't know the identity of the islands?" questioned Alex Retraubun, a government official in charge of small islands and leader of the survey.

"So this agenda is quite important, quite strategic, to smooth your policies in the future," he added, speaking in his office in the ministry of marine and fisheries in central Jakarta, with a large map of Indonesia pinned to the wall.

The issue has become a hot topic after Indonesia upset neighbouring Singapore recently by banning sand exports to the city state, blaming sand mining for literally wiping some of its islands off the map.

The government says it has 17,504 islands, but Retraubun said not all officials are clear about the numbers.

ISLAND-HOPPING

"If you pay attention to our important persons' speeches sometimes the number of islands varies with the speakers. We really need to make sure we have a definitive number."

Retraubun was born on a small island in the remote Moluccas region of eastern Indonesia. He went on to study coastal management at Britain's Newcastle University.

His team is on the last leg of a three-year project to visit every island in Indonesia. Going to the islands, he says, is needed to ensure something is actually an island rather than a clump of mangroves partly submerged at high tide.

According to the U.N. convention on the Law of the Sea, an island is a naturally formed area of land, surrounded by water, which is still exposed at high tide.

The survey team takes the coordinates of an island it visits, notes what is there, whether it is occupied and, if so, what is the makeup of the community. The team interviews the inhabitants.

Far less than half of Indonesia's islands are inhabited and it has yet to officially name more than half.

A marine ministry official said satellite data shows at least 700 are occupied. However, highlighting the sketchy data and hazy definitions, some sources put the number at about 6,000.

Under U.N. rules, the name of an island can be recognised if it is known by at least two local people.

Problems arise, though, when islands have the same name.

"You find almost, let's say, seven islands with the same name and that is confusing," said Retraubun.

In another case, he said an island in West Nusa Tenggara province was being renamed because the western name it had did not sit well with the Muslim population in the outlying area.

Nationally the island has been known as Pulau Sofia Luisa.

"Once we finish this survey then all the names should be standardised."

He also noted the importance of naming islands, or even just rocks, particularly in disputed border areas.

"If that rock is in a border area that is quite strategic because from that rock you measure your maritime border."

Retraubun said Indonesia had learned a lesson from a dispute with Malaysia over sovereignty of the islands of Sipadan, a popular diving resort, and Ligitan in the Sulawesi sea.

The International Court of Justice ruled in 2002 that the islands belonged to Malaysia, based on evidence that Kuala Lumpur was doing more on the islands to indicate its authority.

TOURISM AND CLIMATE CHANGE

Retraubun believes there is still huge potential for tourism, pointing to successful Dutch development of eco-resorts in the diving area of Raja Ampat off Papua province.

"If you're talking about tourism then the isolation is actually an asset," he said.

In contrast, Pulau Ayer's proximity to the teeming capital means that the sea around the palm-fringed beaches of the resort island, which can easily be walked round in 10 minutes or so, is often murky and strewn with rubbish.

Retraubun said he wanted massive investment to come to the small islands, but was realistic about the challenges.

Indonesia's environment minister Rachmat Witoelar in January said the country could lose about 2,000 islands by 2030 if sea levels continued to rise.

World sea levels are likely to rise by up to 59 cms (23.2 inches) by 2100 and bigger gains cannot be ruled out if ice in Greenland and Antarctica thaws, the U.N. climate panel said in February.

Nicholas Stern, author of an acclaimed report on climate change, has also pointed to Indonesia's vulnerability.

"Island states are very vulnerable to sea level rise and very vulnerable to storms. Indonesia with 17,000 islands of course is particularly vulnerable," he said on a recent visit to Jakarta.

Retraubun said that with the majority of small islands in the country only 1 metre above sea level, there was little Indonesia could do if sea levels rose dramatically.